The information such as the shear strength parameters and the cohesion that obtained from triaxial test can be used to check the safety and predict the behaviors of long-term stability of slopes, earth fills and earth retaining structures.
The analysis carried out in terms of total stress obtained from undrained test can be used to investigate the initial stability of the foundation of a structure or embankment on saturated clay. Alternatively, the analysis can also be used to determine the initial stability of open cut or sheet piled excavation made in clay and the stability against bottom heave of a deep excavation in clay.
Moreover, stability of impervious rolled field can be investigated through the test.
Besides, the analysis on the stability of the clay foundation of an embankment or dam where the rate of construction permits partial consolidation can also be determined in terms of effective stress by using the values of c and fi obtained from drained test or consolidated-undrained test.
Advantages and disadvantages of the test Advantages: I.The control of drainage conditions to allow for different types of test: drained and undrained conditions. II.The possibility of the measurement of pore pressure III.The possibility to allow the soil to be sheared to failure in its natural weakest plane. IV.The shear strength parameters obtained is more accurate than those obtained from shear box test.
Disadvantages: I.Influence of the value of intermediate principal stress. In many practical problems approximating to plane strain, the intermediate principal stress is greater then the minor principal test.
II.Change in principal stress direction In problems where the direction of the major principal stress changes steadily under the applied stress, this restriction limits the accuracy with which pore pressure can be predicted. III.Influence of end restraint Friction between the ends of the specimen and the rigid end caps necessary to transmit the axial load restrict lateral deformation adjacent to those surfaces. IV.Duration of test The duration of test commonly used in the triaxial apparatus and the parameters by which the results are expressed are open to criticism on the grounds that they take no account of the phenomena of creep in soil.